Unsaturated polyesters of nitrilotriacetic acid,a polyhydric alcohol and an unsaturated polycarboxylic acid

ABSTRACT

NOVEL THERMOSETTING ESTERS ARE PROVIDED BY REACTING NITRILOTRIACETIC ACID WITH AN UNSATURATED HYDROXY COMPOSITION. PREFERABLY THE NITRILOTRIACETIC ACID IS REACTED WITH A POLYHYDRIC ALCOHOL AND THEN WITH A POLYCARBOXYLIC COMPOUND, WHEREIN AT LEAST ONE OF THE POLYHYDRIC ALCOHOL AND THE POLYCARBOXYLIC COMPOUND CONTAIN ALIPHATIC CARBONTO-CARBON UNSATURATION. THE UNSATURATED ESTERS CAN BE CURED WITH AN OLEFINIC CROSS-LINKING AGENT TO FORM THERMOSET COMPOSITIONS USEFUL AS COATINGS AND IN CASTINGS.

United States Patent Office UNSATURATED IOLYESTERS NITRILOTRI- ACETIC ACID, A POLYHYDRIC ALCOHOL AND AN UN SATURATED POLYCARBOXYLIC ACID Bruce N. Wilson, Niagara Falls, N.Y., assignor to Hooker Chemical Corporation, Niagara Falls, N.Y., a corporation of New York No Drawing. Filed Jan. 26, 1968, Ser. No. 700,688 Int. Cl. C08f 21/02; C08g 17/12 US. Cl. 260-870 6 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION It has not been previously known to utilize nitrilotriacetic acid (a tightly structured tricarboxylic acid containing an amino nitrogen) in the formation of thermosetting esters. One skilled in the art would expect poor properties and reactivity from the acid because of the presence of the amino nitrogen. It was therefore surprising to discover that nitrilotriacetic acid could be employed in the production of thermosetting esters which can be cured with an olefinic cross-linking agent to form thermoset compositions useful as coatings and in castings. Also fortuitous, is the economy involved in the preparation of the polyesters versus the use of other tricarboxylic acids and similar structures known to the art.

' It is the object of this invention to provide novel unsaturated esters of nitrilotriacetic acid. It is also the object of this invention to provide thermosetting esters which can be cured with an olefinic cross-linking agent to form thermoset compositions. A further object of this invention is: to provide novel compositions useful as coatings and in castings. Other objects of this invention will become apparent from the following disclosure.

SUMMARY OF THE INVENTION This invention relates to novel thermosetting esters and cured thermoset compositions. More particularly, the invention relates to novel thermosetting esters which are provided by reacting nitrilotriacetic acid with an unsaturated hydroxy composition and to the thermoset compositions produced by curing said esters with an olefinic crosslinking agent. A preferred aspect of the invention relates to a polymerizable ester of components comprising (1) nitrilotriacetic acid, (2) a polyhydric alcohol, and (3) a polycarboxylic compound, wherein at least one of said polyhydric alcohol and polycarboxylic compound contain aliphatic carbon-to-carbon unsaturation.

DESCRIPTION OF THE PREFERRED EMBODIMENT In accordance with this invention, there is provided an ester produced by reacting nitrilotriacetic acid with an unsaturated hydroxy composition. The unsaturated hydroxy composition can take the form of any aliphatically unsaturated monohydric alcohol or any polyhydric alcohol. When a polyhydric alcohol is employed, the resulting polyester can be further reacted with a polycarboxylic compound, wherein either or both the polyhydric alcohol 3,555,118 Patented Jan. 12, 1971 and the polycarboxylic compound contain aliphatic carbon-to-carbon unsaturation.

Typical monohydric alcohols containing aliphatic carbon-to-carbon unsaturation include those alcohols derived from ethylene; propene; butene; pentene; hexene; 3,3-dimethyl-l-butene; and the like. Typical polyhydric alcohols include ethylene glycol; diethylene glycol; propylene glycol; dipropylene glycol; 1,4-butanediol; 1,4-butenediol; 1,4-butynediol; 1,3-butanediol; 1,2-butanediol; 1,2-pentanediol; 1,3-pentanediol; 1,4-pentanediol; 1,5-pentanediol; 1,6-hexanediol; neopentyl glycol; 2,2,4-trimethyl- 1,3-pentanediol; glycerol; hexanetriol; butanetriol; trimethylol propane; trimethylmethane; pentaerythritol; mannitol; and the like. In the preferred process of this invention, the nitrilotriacetic acid is reacted with a glycol, of which ethylene glycol is preferred. The alcohol is employed in sufficient quantity to esterify substantially all of the carboxyl groups of the nitrilotriacetic acid.

Suitable polycarboxylic compounds include polycarboxylic acids or acid anhydrides or acid halides. Examples of unsaturated compounds are the respective compounds of maleic; fumaric; substituted maleic and fumaric such as citraconic, chloromaleic, mesaconic and pyrocinchoninic; acetylene dicarboxylics, substituted succinics such as aconitic and itaconic; and the like. In the preferred embodiment of this invention, an unsaturated polycarboxylic compound is employed, and the preferred compound is maleic acid, anhydride or halide. The polycarboxylic compound is employed in suflicient quantity to esterify substantially all of the free hydroxyl groups of the alcohol. If a one-step process is employed, as described hereinafter, the compound is employed so as to leave unesterified sufficient hydroxyl groups to esterify substantially all of the nitrilotriacetic acids carboxyl groups.

The following synthesis procedure is typical of a twostep process useful in preparing the preferred ester of this invention. A reaction vessel was fitted with a stirrer, nitrogen inlet tube, thermometer, and a steam jacketed partial condenser fitted to a water condenser and a water trap. The nitrilotriacetic acid and glycol were charged initially and pre-esterified at 170-180 degrees centigrade under agitation and an inert nitrogen sparge until a clear homegenous ester resulted. The charge was then cooled to degrees centigrade, the polycarboxylic compound added, and the esterification continued until the desired level is attained, usually measured by the acid number technique or by other conventional means. The two-step processes are preferred although one-step processes can be utilized in the preparation of the polyester by mixing nitrilotriacetic acid into a reaction mixture of the glycol and polycarboxylic compound at a temperature of about 175 to 180 degrees centigrade. A nitrogen or inert gas purge or pad is preferably used throughout the reaction.

The one-step and two-step processes described above can be carried out at temperatures of -200 degrees centigrade, although temperatures of about -180 degrees centigrade are preferred. The time necessary to complete the above-described oneor two-step processes may vary from l-36 hours, although times of from 3-30 hours are preferred and times of from 4-20 hours are most preferred.

The resulting reaction product is a nitrilotriacetic acid based ester containing aliphatic carbon-to-carbon unsaturation. The ester is then mixed with a polymerizable com pound containing aliphatic carbon-to-carbon unsaturation.

The polymerizable compound containing aliphatic carbon-to-carbon unsaturation is selected from the conventional olefinic or ethylenically unsaturated cross-linking agents. Typical compounds include styrene, diallyl phthalate, diallyl isophthalate, triallyl cyanurate, acrylic acid,

4 methacrylic acid, methylmethacrylate (and other acrylic room temperature catalyst system. The casting was rigid, and methacrylic esters), vinyl toluene, chlorostyrene, rather than a rubbery, solid and had a Barcol hardness methylstyrene and the like. The compound generally comf prises from about 25 to about 50 weight percent of the Examples uncured mixture- 5 Fllowing the procedure of Examples 1 and 2, useful It will be recognized that conventional polymerization castings are prepared from the following combinations of inhibitors, such as hydroquinone, benzylquinone, trinitropolyhydric alcohols, polycarboxylic compounds and olebenzene, picric acid and the like; polymerization catalysts fiuic cross-linking agents with the nitrilotriacetic acid Polycarboxylic Olfinie cross- Aleohol compound linking agent Example:

Malcic anhydridc Styrene. o Do.

Do. E umaric acid Do.

do Diallyl phatlilatc. s d0- Maleicanhydride Methylmcthacrylate. 9 .tlo ..d0 Methylstyrene.

such as benzoyl peroxide, acetyl peroxide, methyl ethyl Various changes and modifications can be made in the ketone peroxide, and the like; dyes; pigments; plasticizers; process and products of this invention without departing lubricants; and various other modifying agents are confrom the spirit and scope of the'invention. The various templated as being incorporated in certain formulations embodiments of this invention disclosed herein serve to to produce compositions embraced in this invention in further illustrate the invention but are not intended to order to obtain or accentuate any given property. limit it. v

The polymerization conditions for effecting the cross- I claim: linking reaction between the unsaturated esters of this in- 1. A polymerizable polyester of ingredients consisting vention and the olefinic cross-linking agent may be essentially of (1) nitrilotriacetic acid, (2) a polyhydric selected from a wide variety of techniques but usually inalcohol, and (3) a polycarboxylic compound containing volve the application of heat or light. Although pressure aliphatic carbon-to-carbon unsaturation. is not a required condition for effecting polymerization of 2. The ester of claim 1 wherein said polyhydric alcohol the polymerizable mixtures embraced Within this invenis ethylene glycol and wherein said polycarboxylic comtion, it is sometimes advantageously employed, particupound is maleic anhydride. larly when, it is desired to make laminates in a pre-formed 3 A 1 i abie mixture comprising (A) a 1 P The temperature at which Polymerization i5 eiTecerizable polyester of ingredients consisting essentially of i dfipehds on a Variety of factors, Particularly the boil- (1) nitrilotriacetic acid, (2) a polyhydric alcohol, and (3) s Poiht 0f the oiefihic F$$"iihkihg agent and the a polycarboxylic compound containing aliphatic carbonthermic characteristics of the polymerization mixture. A to carbon unsaturation d a l i bl lempefhihfe is selected which will give a Suitable reaction pound containing aliphatic carbon-tocarbon unsaturation. rate and yet not cause substantial volatilization, in the 4 The mixture f Claim 3 wherein i l h d i Case of Producing y thick Castings, which will not P 40 alcohol is dihydric, said polycarboxylic compound is dih a Product which is t h carboxylic and contains ethylenic unsaturation, and where The following examples are presented to illustrate the in said polymerizable compound is monomeric d novel compounds of this invention. It is to be understood i ethylenic unsaturation. P h examples not to be.construed as llmltmg the 5. The mixture of claim 4 wherein said polyhydric Invention tempplamres are m deg.reS.S Ceinngrade and alcohol is ethylene glycol, said polycarboxylic compound all parts are by Welght unless otherwise mdlcated' is maleic anhydride, and said polymerizable compound is Example 1 styrene.

A charge of 191 grams of nitrilotriacetic acid and 557 mixture 3 whel} polymerized to an fuslble, insoluble resinous composition.

grams of ethylene glycol was heated with stirring at a temperature of 174-195 degrees centigrade until the References Cited nitrilotriacetic acid triester was formed as measured by the amount of Water distilled out of the mixture. There- UNITED STATES PATENTS after, the reaction mixture was stripped of unreacted eth- 3,197,439 7/1965 Frey 260--75 ylene glycol and the acid number was determined to be 3,223,56 12 1965 Bolt n 260 29.2 below 5 mg. KOH per gram. A charge of 284 grams of 3,275,709 9 9 Wooster at 1 2 61 maleic anhydride was added and the mixture heated to 3,279940 10/1966 Francis et aL 117 94 100-110 degrees centigrade for two hours. The tempera- 3,373,144 3/1968 Janssen et a1 ture was then raised to 160 degrees centigrade and subsequently lowered to degrees centigrade, F REIGN PATENTS no 7 Example 2 6 2/1939 France.

Forty parts of styrene was added to parts of the WILLIAM H SHORT Pnmary Exammer product of Example 1 with 0.1 percent toluhydroquinone M, GOLDSTEIN Assistant E i and the mixture heated to 120 degrees centigrade. U5

A casting was made employing 1 percent methyl ethyl U.S.. Cl. X.R. kctone peroxide and 0.2 percent cobalt naphthenate as a 260- @3 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. ,555, 18 Dated January 12, 1971 Inventor(s) Bruce N. Wilson It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

At column 1 1 ine 30, before "reactivity" read "uncontrol Iable".

At column 2, I ine l -I, for "homegenous" read "homogenous".

At column in the Table at Example 7, For "Dial l yl phathlate" read "DiaI 1y] phthalate".

Signed and sealed this 10th day of August 1971.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

EDWARD M.FLETCHER, JR

Commissioner of Patents Attesting Officer 

